(Alkenyloxy)-, (alkynyloxy) and (cyanoalkoxy) alkoxyphenyl ureas and their use as herbicides

ABSTRACT

This invention relates to novel (alkenyloxy), (alkynyloxy) and (cyanoalkoxy) alkoxyphenyl ureas and their use as herbicidal agents.

This is a division of application Ser. No. 283,603 filed Aug. 24, 1972, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention pertains to new chemical compounds and their use as herbicides.

2. Description of the Prior Art

Phenylureas have been known for sometime to be herbicidal. Examples are the phenylureas claimed in U.S. Pat. Nos. 2,655,445 (1953) and 2,960,534 (1960).

Additionally, 4-alkyloxymethoxy phenylureas are disclosed in Netherland's Pat. NE No. 69,06047 (basic SW 5829/68).

Although (alkynyloxy)phenyl ureas are known to the art (e.g., to Ciba, Belgian BE Pat. No. 756,314) alkynyloxyalkoxy and alkenyloxyalkoxy substituted phenylureas are novel. They also offer advantageous selectivity properties and activity compared with the aforementioned art.

SUMMARY OF THE INVENTION

The invention relates to novel (alkenyloxy)alkoxy phenylureas, (alkynyloxy)alkoxy phenylureas and cyanoalkoxyalkoxy phenylureas represented by the formula: ##STR1## wherein X is hydrogen, halogen, alkyl C₁ -C₄, alkoxy C₁ -C₄, monohaloalkyl C₁ -C₄, dihaloalkyl C₁ -C₄, trihaloalkyl C₁ -C₄ or nitro; Y is ##STR2## R₁, R₂ and R₃ each represent hydrogen, alkyl C₁ -C₄ or alkoxy C₁ -C₄ ; R₄, R₅, R₆ and R₇ each represent hydrogen or methyl; R₈ is --CN, ##STR3## or --C|C--R₁₀ ; R₉ is hydrogen, halogen or methyl; R₁₀ is hydrogen, methyl, halogen or halomethyl; with the proviso that the members represented by X and Y are respectively attached to the carbons in the ring which are meta- and para- to the ring carbon attached to the nitrogen or they are respectively para- and meta- to the ring carbon attached to the nitrogen and a process for controlling undesirable vegetation therewith.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is novel (alkenyloxy)alkoxy phenylureas, (alkynyloxy)alkoxy phenylureas and cyanoalkoxy alkoxyphenylureas defined in detail in the Summary above, and a method for controlling undesirable plant species by applying a herbicidally effective amount of a compound of the above structure to the foliage of the undesirable plants or to soil containing seeds of the undesirable plants.

As used in the specification and claims, the term "halogen" is intended to include fluorine, chlorine, bromine and iodine.

In accordance with this invention, compounds having the structure: ##STR4## where X, Y, R₁, R₂ and R₃ are as described above, can be prepared by dissolving a ureido phenol (II) of the structure: ##STR5## where R₁, R₂, R₃ and Y are as described, in a lower alcohol, preferably methanol or ethanol, and treating the resulting mixture with an alkali metal. The alkali metal is preferably in the form of an alkali metal alkoxide, alkali metal hydroxide or butyl lithium in ether. Representative alkoxides and hydroxides are sodium methoxide, sodium ethoxide, potassium t-butoxide, sodium hydroxide and potassium hydroxide. The thus-prepared reaction mixture is then gently heated at reflux, i.e. 65° to 78° C., for about 30 minutes and the solvent removed. The product (III) is dried by azeotropic distillation using benzene, toluene or similar solvent and has the formula: ##STR6## where X, R₁, R₂ and R₃ are as described above and M represents an alkali metal. The dry product (III) obtained from this reaction is then suspended in a dry loweralkylketone such as acetone, methylethylketone, or the like, maintained at between about 0° and 30° C. and the appropriate cyanoalkyl-, alkenyl- or alkynyl- chloroalkyl ether (IV) slowly added thereto with continuous stirring. The reaction is exothermic and almost instantaneous. However, in practice it is generally desirable to continue stirring the reaction mixture for about 30 minutes to 24 hours after addition is complete.

The reaction mixture is then poured into about four volumes of ice water containing from about 1% to 10% of an alkali metal carbonate or acetate. After stirring for a period of time, usually up to 5 hours, solid product generally forms and can be separated by any convenient means such as filtration or centrifugation. In some cases, however, chloroform extraction, evaporation and crystallization of the residue may be required. An advantageous variation of this process involves the preparation of the salt III in a solvent in which it remains in solution so that the addition of the appropriate chloroalkyl ether may be made to the solution e.g., DMF is a useful solvent for a homogeneous reaction. Work up by pouring into water as previously described is the method of isolating the product as a precipitate. The reaction can be graphically illustrated as follows: ##STR7## where R₁ -R₈, X and M are as defined above.

Alternatively the phenylureas of the present invention may be prepared from substituted nitrophenols (V). The reaction involves treating the substituted nitrophenol (V) with an alkali metal hydroxide or alkoxide in the presence of a lower alcohol C₁ -C₄ to form the corresponding alkoxide (VI). This product is then treated with the alkenyl or alkynylchloroalkyl ether to form the alkenyloxy or (alkynyloxy)alkoxynitrobenzene (VII) which can be selectively reduced by reaction with lithium aluminum hydride in a solvent, e.g. an ether such as diethyl ether or tetrahydrofuran. The alkenyloxy- or (alkynyloxy)alkoxyaniline (VIII) can then be treated with the appropriate carbamoyl halide, preferably chloride, to yield the desired alkenyloxy- (or (alkynyloxy)alkoxyphenylurea.

In yet another procedure the aniline from above may be treated with phosgene to give a mixture of the isocyanate and carbamoyl chloride. This mixture is then treated with the appropriate amine or alkylamine to yield the desired alkenyloxy- or (alkynyloxy)alkoxyphenylurea (I). The above reactions are graphically illustrated below: ##STR8##

The ureido phenols employed as starting materials in the preferred synthesis route can be prepared by the phosgenation of the appropriately substituted meta- or para- aminophenol in an aprotic solvent to yield the intermediate isocyanate. The isocyanate is then reacted with the appropriate primary or secondary amine to yield the ureido phenol.

Alternatively, the ureido phenols can be prepared by carbamoylation of the aminophenol in an aprotic solvent using a dialkylcarbamoyl chloride or alkylalkoxycarbamoyl chloride in the presence of a base acceptor such as sodium bicarbonate or pyridine.

Among the ureido phenols prepared by the above procedure and useful in the synthesis of the compounds of this invention are:

    __________________________________________________________________________     COMPOUND                    MELTING POINT                                      __________________________________________________________________________     1,1-Dimethyl-3-(3-chloro-4-hydroxyphenyl)urea                                                              211-212° C.                                 1,1-Dimethyl-3-(4-hydroxyphenyl)urea                                                                       208-210° C.                                 1,1-Dimethyl-3-(3-hydroxyphenyl)urea                                                                       195-197° C.                                 1-(3-Chloro-4-hydroxyphenyl)-3-methylurea                                                                  188-189° C.                                 1-(4-Hydroxyphenyl)-3-methylurea                                                                           164-165° C.                                 1-(3-Hydroxyphenyl)-3-methylurea                                                                           139-140° C.                                 3-(4-Hydroxyphenyl)-1-methoxy-1-methylurea                                                                 143-145° C.                                 3-(3-Chloro-4-hydroxyphenyl)-1-methoxy-1-methylurea                                                        133-134° C.                                 1,1-Dimethyl-3-(4-hydroxy-3-nitrophenyl)urea                                                               134-138° C.                                 1-(4-Hydroxy-3-nitrophenyl)-3-methylurea                                                                   195-197° C.                                 1-Ethyl-3-(3-chloro-4-hydroxyphenyl)urea                                                                   156-158° C.                                 1-(3-Chloro-4-hydroxyphenyl)-3-n-propylurea                                                                169-170° C.                                 1-(3-Chloro-4-hydroxyphenyl)-3-iso-propylurea                                                              180.5- 181.5° C.                            1-n-Butyl-3-(3-chloro-4-hydroxyphenyl)urea                                                                 145-148° C.                                 1-(3-Chloro-4-hydroxyphenyl)-3,3-diethylurea                                                               136-137° C.                                 __________________________________________________________________________

The chloroalkylalkynyl (or alkenyl) ethers utilized as intermediates in the preferred procedure for the preparation of the compounds of this invention can be prepared by reacting the appropriate alkynyl or alkenyl alcohol with an aldehyde such as para- formaldehyde and hydrogen chloride at -30° C. to +20° C. in the absence or presence of a solvent (e.g. methylene chloride). Among the compounds prepared by this procedure are: chloromethyl 2-propynyl ether, boiling point 38° C. to 43° C./34 to 36 mm.; chloromethyl 1-methyl-2-propynyl ether, boiling point 36° C. to 39° C./32 mm.; chloromethyl 1,1-dimethyl-2-propynyl ether, boiling point 39.5° C. to 41.5° C./16 to 17 mm.; 2-methylallyl chloromethyl ether, boiling point 60° C. to 63° C./44 mm.; allyl chloromethyl ether, boiling point 38° C. to 46° C./70 mm.; 1-chloroethyl 1,1-dimethyl-2-propynyl ether, boiling point 57° C. to 58° C./55 mm.; 1-chloroethyl 1-methyl-2-propynyl ether, boiling point 68° to 70° C./111 to 115 mm.; and 1-chloroethyl 2-propynyl ether, boiling point 57° C. to 63°/57 to 60 mm.

The compounds of this invention, especially those having the structure: ##STR9## where R₂, R₃, X and Y are as described above, are highly effective herbicidal agents. They provide selective control of a wide variety of broadleaf weeds and grasses and may be used for either preemergence or postemergence control of undesirable plants. They may be used alone or in combination with other herbicides and are particularly effective when utilized for the control of undesirable weeds and grasses in the presence of agronomic crops such as corn, cotton, soybeans and rice.

The active compounds can be incorporated in liquid or solid formulations and applied as such to the foliage of undesirable plants or to soil containing seeds of undesirable plants.

Among the solid formulations which can be prepared are dusts, dust concentrates, wettable powders and granular formulations.

Dusts are usually prepared by dissolving the active ingredient in a lower alcohol (e.g. methanol, isopropanol or butanol) or a ketone (e.g. acetone, methylethylketone or cyclohexanone) and spraying the thus-prepared solution on a finely divided carrier such as attapulgite, kaolin, diatomaceous earth, or the like. Dusts usually contain about 1% to 15% by weight of the active compound.

Dust concentrates are generally prepared in the same fashion as dusts excepting that about 16% to about 75% by weight of the active compound is applied to the carrier.

Wettable powders are made up in the same manner as the dust concentrates; however, about 1% to 10% by weight of a surfactant is usually added. In some instances, about 1% to 5% by weight of a dispersent and about 1% to 5% of an anionic - nonionic emulsifier is used in place of a single surfactant. In practice, the wettable powders are generally dispersed in water or other suitable liquid and applied to the soil or foliage as a dilute spray.

Surfactants which may be used in preparation of the wettable powders are naphthalene sulfonic acid condensate, polyoxyethylate vegetable oil, Sorbitan monooleate, mono- and diglycerides of fatty acids, alkyl phenoxy polyoxyethylene ethanol and sodium alkylnaphthalene sulfonate. The mono-calcium salt of a polymerized alkyl aryl sulfonic acid and sodium lignin sulfonate are representative of dispersants which can be used in the wettable powder formulations. Also, MAL-77L, an anionic-nonionic blend containing calcium dodecylbenzene sulfonate, is representative of the emulsifiers which may be used in the wettable powders.

Granular formulations can be prepared by applying an alcoholic or ketonic solution of the active material to a granular sorptive carrier such as attapulgite, kaolin, activated carbon or corn cob grits. Non-sorptive carriers such as granular limestone, walnut shell, cocoanut shell or sand may be used in the preparation of granular formulations by (1) wetting the granules with a binder solution (e.g., sodium lignosulfonate) or an alcoholic or ketonic solution of the active ingredient, and (2) coating the wetted particles with a dust or dust concentrate containing the active compound or with an inert dusting agent such as talc or clay.

Emulsifiable concentrates can be prepared by dissolving about 25% to 75% by weight of the active compound in a lower alcohol or ketone, as mentioned above, and admixing therewith from about 1% to 10% by weight of an emulsifier. For use in the field, the concentrate is usually dispersed in water or other suitable diluent and applied as a liquid spray.

Effective control of a wide variety of broadleaf weeds and grasses is usually obtained by application of a sufficient amount of the formulated composition to provide about 0.06 pounds per acre to 15 pounds per acre of active compound. Selective control of said weeds and grasses, on the other hand, generally requires only about 0.06 pounds per acre to about 4.0 pounds per acre of the active compound.

This invention is further illustrated by the following examples.

EXAMPLES 1 through 32 3-{3-Chloro-4-[(1,1-dimethyl-2-propynyloxy)methoxy]phenyl} urea ##STR10##

Sodium methoxide (0.54 gram, 0.01 mole) is added to a methanolic solution of 3-(3-chloro-4-hydroxyphenyl)-1,1-dimethylurea (2.14 grams, 0.01 mole) and the mixture heated at reflux during 2 hours. The solvent is removed under reduced pressure and to the residual material dry benzene is added and evaporated off. This procedure is repeated until a dry white powder is obtained. The sodium salt is suspended in dry acetone (50 ml.) and chloromethyl 1,1-dimethyl-2-propynyl ether (1.45 grams, 0.011 mole) is added dropwise with stirring. After the initial exothermic reaction the reaction mixture is allowed to stir for a further 4.5 hours, then cold aqueous sodium carbonate solution (10% w/v, 100 ml.) followed by water (50 ml.) are added.sup.(1) and stirred. The resulting solid.sup.(2) is filtered off, water washed and air dried. Crystallization from benzene-hexane affords 2.2 grams, 70%; melting point 150° C. to 151° C. of Compound 1.

The following compounds (Compounds 1 through 32) are prepared according to the above procedures using the appropriate ureido phenol (II). Among the ureido phenols that may be used in this process are those listed on page 8.

                                      TABLE I                                      __________________________________________________________________________                                           Solvent                                  Com-                                                                               Starting                          of   Melting Analysis                    pound                                                                              Chloromethyl                      Crystal-                                                                            Point    %     %                    No. Ether            Compound Prepared                                                                               lization                                                                            ° C.                                                                            Calculated                                                                           Found                 __________________________________________________________________________          ##STR11##       3-{3-chloro-4-[(1,1- dimethyl-2-propynyloxy)-                                  methoxy]phenyl}-1,1- dimethylurea                                                               benzene- hexane                                                                     150-151 C, 58.0 H,6.2 N,9.0                                                            Cl, 11.4                                                                             C, 58.7 H,6.3                                                                  N,8.3 Cl, 11.4        2                                                                                   ##STR12##                                                                                       ##STR13##                                                                                       ##STR14##                                                                          113.5-114.5                                                                             ##STR15##                                                                            ##STR16##            3                                                                                   ##STR17##       3-{p-[(1,1-dimethyl-2- propynyloxy)methoxy]-                                   phenyl}-1,1-dimethylurea                                                                        benzene- hexane                                                                     75-76   C, 65.2 H,7.3 N,                                                                     C, 65.4 H,7.2 N,                                                               10.1                  4                                                                                   ##STR18##                                                                                       ##STR19##                                                                                       ##STR20##                                                                          114-115                                                                                 ##STR21##                                                                            ##STR22##            5                                                                                   ##STR23##       3-{3-chloro-4-[(1-methyl- 2-propynyloxy)methoxy]-                              phenyl}-1,1-dimethylurea                                                                        benzene- hexane                                                                     106-107                                                                                 ##STR24##                                                                            ##STR25##            6                                                                                   ##STR26##                                                                                       ##STR27##                                                                                       ##STR28##                                                                          98-98.5                                                                                 ##STR29##                                                                            ##STR30##            7                                                                                   ##STR31##                                                                                       ##STR32##       --                                                                                   ##STR33##                                                                              ##STR34##                                                                            ##STR35##            8                                                                                   ##STR36##                                                                                       ##STR37##       --   oil (n.sub.D.sup.25                                                                    C, 60.4 H,6.5 N,                                                                     C, 60.5 H,6.6 N,                                                               10.1                  9                                                                                   ##STR38##       3-{m-[(1,1-dimethyl- 2-propynyloxy)methoxy]-                                   phenyl}-1-methoxy-1- methylurea                                                                 --   oil (n.sub.D.sup.25                                                                    C, 61.6 H,6.9 N,9.6                                                                  C, 62.2 H,6.9                                                                  N,9.2                 10                                                                                  ##STR39##                                                                                       ##STR40##                                                                                       ##STR41##                                                                          95-95.5                                                                                 ##STR42##                                                                            ##STR43##            11                                                                                  ##STR44##                                                                                       ##STR45##       --                                                                                   ##STR46##                                                                              ##STR47##                                                                            ##STR48##            12                                                                                  ##STR49##                                                                                       ##STR50##                                                                                       ##STR51##                                                                          143-145                                                                                 ##STR52##                                                                            ##STR53##            13                                                                                  ##STR54##       1-{3-chloro-4-[(1,1- dimethyl-2-propynyloxy)-                                  methoxy]phenyl}-3- methylurea                                                                   benzene- hexane                                                                     127-128 C, 56.7 H,5.8 N,9.4                                                                  C, 57.0 H,5.9                                                                  N,9.5                 14                                                                                  ##STR55##                                                                                       ##STR56##                                                                                       ##STR57##                                                                          81.5-83                                                                                 ##STR58##                                                                            ##STR59##            15                                                                                  ##STR60##       3-{3-chloro-4-[(1,1- dimethyl-2-propynyloxy)-                                  methoxy]phenyl}-1-methoxy- 1-methylurea                                                         benzene- hexane                                                                     96-97   C, 55.1 H,5.9 N,8.6                                                                  C, 56.0 H,6.0                                                                  N,8.4                 16                                                                                  ##STR61##       1,1-dimethyl-3-{p-[(2- methylallyloxy)methoxy]-                                phenyl}urea      benzene- hexane                                                                     99-100  C, 63.6 H,7.6 N,                                                                     C, 63.0 H,7.9 N,                                                               10.0                  17                                                                                  ##STR62##       1,1-dimethyl-3-{m-[(1,1- dimethyl-2-propynyloxy)-                              methoxy]phenyl}urea                                                                              ##STR63##                                                                          104-105 C, 65.19 H,7.30 N,                                                             10.14 C, 65.7 H,7.2 N,                                                               10.0                  18                                                                                  ##STR64##       1-{p-[(1,1-dimethyl-2- propynyloxy)methoxy]phenyl}                             3-methylurea     benzene                                                                             150-151 C, 64.1 H,6.9 N,                                                                     C, 64.2 H,6.9 N,                                                               10.4                  19                                                                                  ##STR65##                                                                                       ##STR66##                                                                                       ##STR67##                                                                          149-150.3                                                                               ##STR68##                                                                            ##STR69##            20                                                                                  ##STR70##       1-methoxy-1-methyl-3-{p- [(1,1-dimethyl-2-propynyloxy                          )- methoxy]phenyl}urea                                                                          benzene- hexane                                                                     70-71   C, 61.6 H,6.9 N,9.6                                                                  C, 61.4 H,6.8                                                                  N,9.4                 21                                                                                  ##STR71##                                                                                       ##STR72##       hexane                                                                              85-86                                                                                   ##STR73##                                                                            ##STR74##            22                                                                                  ##STR75##       3-{p-[1-(1,1-dimethyl-2- propynyloxy)ethoxy]phenyl}-                           ,1-dimethylurea  hexane- benzene (10:1)                                                              91-93   C, 66.2 H,7.6 N,9.7                                                                  C, 66.3 H,7.8                                                                  N,9.5                 23                                                                                  ##STR76##                                                                                       ##STR77##       benzene- hexane                                                                     111.5-113.5                                                                             ##STR78##                                                                            ##STR79##            24                                                                                  ##STR80##                                                                                       ##STR81##       hexane                                                                              50-53                                                                                   ##STR82##                                                                            ##STR83##            25                                                                                  ##STR84##                                                                                       ##STR85##       --   glassy solid                                                                            ##STR86##                                                                            ##STR87##            26                                                                                  ##STR88##                                                                                       ##STR89##       hexane                                                                              93-95                                                                                   ##STR90##                                                                            ##STR91##            27                                                                                  ##STR92##                                                                                       ##STR93##                                                                                       ##STR94##                                                                          141.5-143                                                                               ##STR95##                                                                            ##STR96##            28                                                                                  ##STR97##                                                                                       ##STR98##                                                                                       ##STR99##                                                                          123-124                                                                                 ##STR100##                                                                           ##STR101##           29                                                                                  ##STR102##                                                                                      ##STR103##                                                                                      ##STR104##                                                                         122-123                                                                                 ##STR105##                                                                           ##STR106##           30                                                                                  ##STR107##                                                                                      ##STR108##                                                                                      ##STR109##                                                                         112-113                                                                                 ##STR110##                                                                           ##STR111##           31                                                                                  ##STR112##                                                                                      ##STR113##                                                                                      ##STR114##                                                                         153-154                                                                                 ##STR115##                                                                           ##STR116##           32                                                                                  ##STR117##      3-{3-chloro-4-[1-(1,1-di- methyl-2-propynyloxy)ethoxy                          ]- phenyl}-1,1-dimethylurea                                                                     benzene- hexane                                                                     101-103 C, 59.17 H,6.52                                                                      C, 59.17 H,6.56                                                                N,8.66                __________________________________________________________________________

EXAMPLE 33 Preparation of 3-{3-Chloro-4-[1-(1,1-dimethyl-2-propynyloxy)-ethoxy]phenyl}-1,1-dimethylurea ##STR118##

To a well-stirred suspension of the potassium salt of 3-chloro-4-hydroxyphenyl-1,1-dimethylurea (0.04 mole) in dry acetone (150 ml.) is added dropwise 1-chloroethyl 1,1-dimethyl-2-propynyl ether (5.9 grams, 0.04 mole). During the addition, an exotherm to 35° C. is observed; the reaction is stirred at room temperature overnight, then poured into an aqueous 10% sodium carbonate solution containing 200 grams of ice, and the mixture stirred vigorously for 30 minutes. The resulting solid is filtered off, water-washed and dried to give 8.5 grams, melting point 99° to 101° C., crystallization from hexane-cyclohexane-benzene gave 4.69 grams (36%), melting point 101° to 103° C.

Analysis Calculated for C₁₆ H₂₁ N₂ O₃ Cl: C, 59.17; H, 6.52; N, 8.62. Found: C, 59.17; H, 6.56; N, 8.66.

EXAMPLE 34 Preparation of 1-Methyl-2-propynylchloromethyl Ether

Hydrogen chloride gas was bubbled into a suspension of paraformaldehyde (30.1 grams, 1 mole) in 3-butyn-2-ol (70.1 grams, 1 mole), with constant stirring, at -30° C. The exotherm was controlled between -15° C. and 5° C., and the hydrogen chloride addition continued until the solid dissolved. Upon completion of the addition, the reaction was allowed to attain 15° C. and sodium chloride added to aid the separation of the organic layer. The upper organic layer was separated and dried over anhydrous calcium chloride for 3 hours and distilled under reduced pressure to give 1-methyl-2-propynylchloromethyl ether, 83 grams, 70%, boiling point 36° C. to 39° C./32 mm.

EXAMPLE 35 Preparation of 1,1-Dimethyl-2-propynylchloromethyl Ether

Hydrogen chloride gas (80 grams, 2.2 moles) was bubbled into a mixture of paraformaldehyde (60.2 grams, 2.0 moles), and 2-methyl-3-butyn-2-ol (168.2 grams, 2.0 mole) in methylene chloride (500 ml.) over a 25 minute period, with constant stirring while maintaining the temperature between 2° to 8° C. Upon completion of the addition, the reaction temperature was allowed to rise to 10° C., then the lower organic phase separated, washed with ice water, separated and dried over anhydrous calcium chloride for 18 hours. The methylene chloride was removed by evaporation and the resulting liquid distilled at reduced pressure to give the chloromethyl ether, 1,1-dimethyl-2-propynylchloromethyl ether, 140 grams, 53%, boiling point 54° to 58° C./37 to 40 mm.

EXAMPLES 36 through 46

Following the procedure of Example 1 and substituting therein the appropriate ureido phenol and alkynyl chloromethyl ether yields the following compounds:

    __________________________________________________________________________     Example                                                                        Number        Structure                                                        __________________________________________________________________________     36                                                                                     ##STR119##                                                                    1,1-dimethyl-3-{p-[2-propynyloxy)-                                             α,α-dimethylmethoxy]phenyl}urea                             37                                                                                     ##STR120##                                                                    1,1-dimethyl-3-{p-[(3-iodo-2-propynyloxy)-                                     methoxy]phenyl}urea                                                     38                                                                                     ##STR121##                                                                    3-{3-bromo-[1,1-dimethyl-4-propynyloxy)-                                       methoxy]phenyl}-1,1-dimethylurea                                        39                                                                                     ##STR122##                                                                    3-{[3-methyl-4-(2-propynyloxy)methoxy]CH.sub.- phenyl}-urea             40                                                                                     ##STR123##                                                                    1,1-dimethyl-3-{[3-trifluoromethyl-4-(2-                                       propynyloxy)methoxy]phenyl]}urea                                        41                                                                                     ##STR124##                                                                    1,1-dimethyl-3-{[3-methoxy-4-(2-propynyloxy)-                                  methoxy]phenyl}urea                                                     42                                                                                     ##STR125##                                                                    1,1-dimethyl-3-{[4-(2-propynyloxy)methoxy-                                     3-nitro]phenyl}urea                                                     43                                                                                     ##STR126##                                                                    1,1-dimethyl-3-{[4-(4-chloro-2-butynyloxy)-                                    methoxy]phenyl}urea                                                     44                                                                                     ##STR127##                                                                    1,1-dimethyl-3-{[4-(2-butynyloxy)methoxy]-                                     phenyl}urea                                                             45                                                                                     ##STR128##                                                                    1,1-dimethyl-3-{[4-(cyanomethoxy)methoxy]-                                     phenyl}urea                                                             46                                                                                     ##STR129##                                                                    1,1-dimethyl-3-{[4-(1,1-dimethylcyanomethoxy)-                                 methoxy]phenyl}urea                                                     __________________________________________________________________________

EXAMPLE 47

The selective postemergence herbicidal activity of the preferred compounds of the present invention is demonstrated by the following tests, wherein a variety of monocotyledonous and dicotyledonous plants are treated with test compounds dispersed in aqueous acetone mixtures. In the tests, seedling plants are grown in two-inch square plastic pots for about two weeks. The test compounds are dispersed in 50/50 acetone/water mixtures containing 0.5% v/v surfactant in sufficient quantity to provide the equivalent of about 0.06 to 10 pounds per acre of active compound when applied to the plants through a spray nozzle operating at 40 psi. for a predetermined time. After spraying, the plants are placed on greenhouse benches and are cared for in the usual manner, commensurate with conventional greenhouse practices. Two weeks after treatment, the seedling plants are examined and rated according to the rating system provided below. The data obtained are reported in the Table below where it can be seen that the preferred compounds are highly effective for the control of undesirable broadleaf weeds and grasses in the presence of the desirable crops, rice, corn, cotton and soybeans.

    ______________________________________                                         Plant Abbreviations:                                                                    LA -  Lambsquarters                                                            MU -  Mustard                                                                  PI -  Pigweed                                                                  BA -  Barnyardgrass                                                            CR -  Crabgrass                                                                GFT - Green foxtail                                                            WO -  Wild oats                                                                COR - Corn                                                                     COT - Cotton                                                                   SOY - Soybean                                                                  RAG - Ragweed                                                                  MG -  Morningglory                                                             R -   Rice                                                                     VE -  Velvetleaf                                                                        % Difference in Growth                                        Rating System:   From the Check*                                              ______________________________________                                         0 - no effect      0                                                           1 - possible effect                                                                               1-10                                                        2 - slight effect 11-25                                                        3 - moderate effect                                                                              26-40                                                        5 - definite injury                                                                              41-60                                                        6 - herbicidal effect                                                                            61-75                                                        7 - good herbicidal effect                                                                       76-90                                                        8 - approaching complete kill                                                                    91-99                                                        9 - complete kill 100                                                          ______________________________________                                          4 - abnormal growth, i.e. a definite physiological malformation but with       an over-all effect less than a 5 on the rating scale.                          *Based on visual determination of stand, size, vigor, chlorosis, growth        malformation and over-all plant appearance.                              

    TABLE II        Postemergence Herbicidal Activity  Compound      of Example  Treatment A      nnual Weeds Crops Number   Structure lb./acre LA MU PI RAG MG VE BA CR      GRF WO COR COT SOY R                           6       ##STR130##       1.00.50.250.13 9989 9979 9999 9990 9972 8210 3100 310 0 3200 3210 6300  3     2      7 9931 3000       2      ##STR131##       1.00.50.250.13 9987 9997 9997 9990 9990 9930 3110 3210 3210 3100 2211   3     2      75 992 2 3110       3      ##STR132##       1.00.50.130.069975 9998 9999 8890 9999 9998 9621 9911 7522 8633 9983    9      999 9953 9733       4      ##STR133##       1.00.250.130.06 9 932 9998 9998 9999 9999 5827 7222 9111 9211 5222 9955      9953 9785 7222       5      ##STR134##       1.00.50.250.13 9997 9999 9999 9999 9999 9999 9821 9922 9 685 9331 9959  9     9      9 9982 8632       1      ##STR135##       1.00.250.130.06 9997 9999 9999 9990 9999 9989 9311 9221 9532 9752 9993  9     9      9 9999 8732       7      ##STR136##       1.00.50.250.13 9532 9851 9953 9890 8750 9220 3110 3110 3110 2100 6321   5     3      75 3221 3100       8      ##STR137##       1.00.50.250.13 9882 9973 9993 99 79 9911 9961 7210 2110 3110 3110 9210  3     3      8 5211 3210       9      ##STR138##       1.00.50.250.13 9933 9831 9992 0000 9810 9950 1110 1110 1110 3220 9931   6     2      9  7222 3110 10       ##STR139##       10.09999999999-- -- -- --       15      ##STR140##       1.00.250.130.02 9999 9999 9999 9992 9996 9993 9651 9972 9992 9651 9963  9     9      9 9995 8 553       16      ##STR141##       2.01.00.5999 998 998 995 999 965 776 983 983 520 200 999 987 531  19       ##STR142##       4.01.00.25 988 998 982 970 983 710 730 8 30 961 820 600 811 851 720  21       ##STR143##       4.0 1.00.250.06 9999 9995 9992 9810 9921 9200 9710 9810 9920 9710 9710  9     3      9  9732 9600       18      ##STR144##       1.00.25 99 99 99 97 99 99 71 91 98 72 20 76 97 82       20      ##STR145##       4.01.00.250.06 9998 9999 9999 9991 9997 9998 9970 99 80 9993 9870 9630  9     9      9 9985 9961       17      ##STR146##       4.01.00.250.06 9998 9992 9990 9720 9992 9820 9710 9810 9950 9820 9920   5     0      98 9852 9820       14      ##STR147##       1.00.250.130.06 9999 9999 9999 9993 9999 9630 9732 9951 9961 9655 9575  9     9      9 9999 8530       22      ##STR148##       0.50.250.130.06 9997 9997 9970 8900 7600 9200 0000 6300 5300 0000 0000  1     1      2 6555 9200       23      ##STR149##       1.00.50.250.13 9999 9999 9998 9909  9331 9970 6300 8300 7300 6110 1000  6     9      9 9888 6150       25      ##STR150##       1.00.50.250.13 9992 9996 9830 8630 8310 9500 5200 8 300 8200 6000 1000  8     5      7 9888 5520       26      ##STR151##       0.500.250.130.06 9999 9999 9999 9990 9992 9600 9862 9889 9977 9620 3111      9975 9998 8 611       27      ##STR152##       4.01.00.5 873 970 999 970 755 000 772 770 500 110 ------ 311 321 100      28       ##STR153##       10.0 9 660000000-- -- -- --       29      ##STR154##       10.08785200000-- -- -- --       30      ##STR155##       4.01.00.5 985 861 996 350 100 000 500 200 000 000 ------ 321 321 000      31       ##STR156##       1.00.250.130.06 9999 9999 9999 9 775 8398 9300 8200 9210 9620 1000      -------- 7523 2111 5800       32      ##STR157##       0.500.250.130.06 9999 9999 9989 9337 9999 9985 8700 9876 9985 3000      610 0 9999 9987 7325

EXAMPLE 48

The selective preemergence herbicidal activity of the compounds of the invention is exemplified by the following tests in which the seeds of a variety of monocotyledonous and dicotyledonous plants are separately mixed with potting soil and a one half inch layer is placed on top of approximately 1 1/2 inch of soil in separate two-inch square plastic pots. After planting, the pots are sprayed with the selected aqueous acetone solution containing test compound in sufficient quantity to provide the equivalent of about 0.13 to 4 pounds per acre of test compound per pot. The treated pots are then placed on greenhouse benches and cared for in accordance with greenhouse procedures. Three weeks after treatment, the tests are terminated and each pot is examined and rated according to the rating system set forth in the preceding example. The tabulated results of these tests establish the selective herbicidal proficiency of the test compounds, when properly applied, for controlling a variety of undesirable plant species. The data also indicate broad spectrum activity of the compounds when applied at relatively high rates. Results are reported in the Table below.

    TABLE III       Preemergence Herbicidal ActivityCompound      of Example  Treatment      Annual Weeds Crops Number   Structure lb./acre LA MU PI RAG MG VE BA CR      GRF WO COR COT SOY R                           6       ##STR158##       4.01.00.50.25 9992 9982 9993 9960 9960 9500 9860 9850 97 32 9610 9700   0     0      90 9900 9820       2      ##STR159##       4.01.00.50.25 9998 9998 9999 9970 9972 9980 9870 9981 9870 9810 9700    0      997 99 01 9721       3      ##STR160##       4.01.00.250.13 9999 9999 9999 9999 9999 9999 9999 9998 9996 9776 9711   9     2      99 9983 9998       4      ##STR161##       4.01.00.25 0.13 9999 9970 9999 9960 9970 9930 9982 9971 9972 9931 9310  5     0      9 9900 9960       5      ##STR162##       4.01.00.250.13 9999 9997 9999 9990 9981 9900 99 95 9971 9953 9711 8810  7     0      9 9310 9962       1      ##STR163##       4.01.00.250.13 9999 9999 9999 9995 9822 9890 9987 9973 9920 7711 9710   1     0      98 9910 9811       7      ##STR164##       4.01.00.50.25 9995 9993 9999 9900 9510 9620 9321 9310 9520 9600 8100    0      960 9300 9710       8      ##STR165##       4.01.00.50.25 9985 999 5 9999 9955 9700 9820 9860 9860 9700 7511 3210   0     0      98 9700 9930       9      ##STR166##       4.01.00.50.25 9989 9998 9997 9900 9900 9920 9820 9700 9500 7 210 2100   0     0      90 9000 9710       11      ##STR167##       1.00.5 989998 9231 80 97 86 90 31 21 00 50 91       10      ##STR168##       1.00.50.25 998 990 999 992 990 920 999 996 991 850 330 820 93 0 981  12       ##STR169##       4.01.00.5 998 999 999 990 973 990 873 996 970 963 300 000 950 733  13       ##STR170##       4.01.00.50.25 9998 9999 9999 9970 9 932 9998 8700 9900 9700 7200 2000      5----0 9952 7200       14      ##STR171##       4.01.00.250.13 9998 9993 9999 9930 9900 9900 9970 9970 9970 9900 9700   0      990 9600 9800       15      ##STR172##       4.01.00.250.13 9999 9999 9999 9300 9962 9999 8850 9820 8800 8008 2000   0     0      93 9510 6200       16      ##STR173##       2.01.00.5 0.25 9870 9999 9985 5000 9100 9320 7650 8710 7310 1100 2110      92--0 9000 3230       19      ##STR174##       4.01.00.25 983 991 998 920 910 910 730 850 83 0 930 500 931 830 720  21       ##STR175##       4.01.00.25 998 999 999 992 990 980 972 982 981 991 930 995 983 861  20       ##STR176##       4.01.00.25 999 99 9 999 995 996 999 998 988 998 995 970 998 982 983  18       ##STR177##       1.00.250.06 997 999 998 970 910 995 971 980 930 310 000 520 710 610  17       ##STR178##       4.01.00.25 999 999 999 990 995 998 982 982 981 992 752 990 991 991  23       ##STR179##       4.01.0 99 99 99 93 71 89 65 87 60 72 20 10 35 31       25      ##STR180##       1.00.50.25 875 873 973 750 591 950 000 300 800 100 0--0 910 720 200  26       ##STR181##       1.00.50.250.13 9989 9988 9999 9770 9921 9830 9822 9983 9510 9761 2000   0     0      11 7--20 7301       27      ##STR182##       4.01.0 99 97 97 87 90 10 60 76 50 10 20 70 50 10       29      ##STR183##       4.01.0 98 82 82 89 44 00 10 30 10 00 00 70 50 00       30      ##STR184##       4.01.0 87 99 35 78 00 00 20 20 00 00 00 20 20 00       31      ##STR185##       2.01.00.5 999 999 999 997 952 999 765 985 762 210 500 300 610 750  32       ##STR186##       4.01.0 97 99 90 00 11 70 30 00 00 00 00 00 00 00 

I claim:
 1. A compound represented by the formula: ##STR187## wherein R₂, R₄, R₆ and R₇ are hydrogen or methyl.
 2. A compound according to claim 1: 1,1-dimethyl-3-{m-[(2-propynyloxy)-methoxy] phenyl} urea.
 3. 1,1-Dimethyl-3-{m-[(1,1-dimethyl-2-propynyloxy)methoxy]phenyl} urea. 